采用清水、氨水以及CaO等三种中和剂对铀矿堆浸尾渣进行中和试验,以确定合适的中和剂。将确定的中和剂以及渣浆浓度、灰渣比按一定比例配制成胶结充填体标准试样,采用RMT-150B岩石力学试验机,测试其不同龄期的抗压强度。根据测试结果,选用渣浆浓度为80%、灰渣比为18的胶结充填体对某铀矿工业性试验采场进行了充填,同时还对其进行了应力测试。研究结果表明,CaO是比较理想的中和剂,其耗量为尾渣干重的0.2%;渣浆浓度、灰渣比是影响堆浸尾渣胶结充填体强度的关键因素,其强度与渣浆浓度成正比,与灰渣比成反比;渣浆浓度为80%、灰渣比为18的堆浸尾渣胶结充填体,龄期为7d时,其抗压强度大于2 MPa,塌落度为13mm;选用该配比的堆浸尾渣胶结充填体的试验采场应力测试结果远低于其抗压强度,有效地控制了该矿试验采场深部开采的地压。
The water soaking, the ammonia and the CaO are used to neutralize uranium tailings from heap leaching for determining the suitable neutralization. Samples, with determined neutralization, slurry concentrations, cement-tailing ratios and different curing time, are prepared by using the heap leaching tailing cemented backfills, and the uniaxial compressive strengths are measured by using RMT-150B rock mechanics testing machine. Based on the test results, the heap leaching tailings cemented backfills, with the slurry concentration of 80% and cement- tailing ratio of 11 8, is used to fill the test stope in a uranium mine, and the stress measurements are conducted for the backfills. The results show that the CaO, the consumption of 0.2% of the dry weight of the tailings, is the suitable neutralization. The slurry concentration and cement-tailing ratio are the key factors to influence on the compressive strength of the backfills, meanwhile, the compressive strength of the backfills increase with the increase of the slurry concentration, while decrease with the increase of the cement-tailing ratio. The compressive strength of backfills, with the slurry concentration of 80 % and cement-tailing ratio of 1 : 8, is larger than 2 MPa at the solidification duration of 7 days, and the collapsbillity is 13 mm. The stress measurements of the determined backfills is lower than its compressive strength, which means that it can be used to effectively control the ground pressure in deep stope mining.